Method for producing powder dispersant composition for hydraulic compositions

Abstract

The present invention is a method for producing a powder dispersant composition for hydraulic compositions including, drying a mixture containing a copolymer having constituent unit (1) represented by the following formula (1) and constituent unit (2) represented by the following formula (2) and water to produce a powder containing the copolymer, wherein:when the copolymer is a copolymer whose n in constituent unit (2) is less than 40, the mixture is dried by a thin film drying method or a spray drying method with a pH of 11 or more and 14 or less;when the copolymer is a copolymer whose n in constituent unit (2) is 40 or more and less than 80, the mixture is dried by a thin film drying method or a spray drying method with a pH of 9 or more and 14 or less; andwhen the copolymer is a copolymer whose n in constituent unit (2) is 80 or more, the mixture is dried by a thin film drying method or a spray drying method with a pH of 7 or more and 14 or less,wherein R1 and R3 are the same or different and individually represent a hydrogen atom or a methyl group; R2 and R4 are the same or different and individually represent a hydrogen atom or an alkyl group with 1 or more and 3 or less carbons; M represents a hydrogen atom, an alkali metal, an alkaline-earth metal, ammonium or an organic ammonium; p represents a number of 0 or more and 2 or less; q represents a number of 0 or 1; and n represents an average number of added moles and a number of 5 or more and 150 or less.

1 . (canceled) 
     
     
         2 : A method for producing a powder dispersant composition for hydraulic compositions comprising, drying a mixture containing a copolymer having a constituent unit (1) represented by formula (1) and a constituent unit (2) represented by formula (2) and water to produce a powder containing the copolymer, wherein:
 when the copolymer is a copolymer whose n in the constituent unit (2) is less than 40, the mixture is dried with a pH of 11 or more and 14 or less;   when the copolymer is a copolymer whose n in the constituent unit (2) is 40 or more and less than 80, the mixture is dried with a pH of 9 or more and 14 or less;   when the copolymer is a copolymer whose n in the constituent unit (2) is 80 or more and less than 100, the mixture is dried with a pH of more than 9 and 14 or less; and   when the copolymer is a copolymer whose n in the constituent unit (2) is 100 or more, the mixture is dried with a pH of 7 or more and 14 or less,   
       
         
           
           
               
               
           
         
         wherein R 1  and R 3  are the same or different and individually represent a hydrogen atom or a methyl group; R 2  and R 4  are the same or different and individually represent a hydrogen atom or an alkyl group with 1 or more and 3 or less carbons; M represents a hydrogen atom, an alkali metal, an alkaline-earth metal, ammonium or an organic ammonium; p represents a number of 0 or more and 2 or less; q represents a number of 0 or 1; and n represents an average number of added moles and a number of 5 or more and 150 or less. 
       
     
     
         3 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein the mixture is dried by heat drying. 
     
     
         4 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein the mixture is dried by a thin film drying method or a spray drying method. 
     
     
         5 . (canceled) 
     
     
         6 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein a proportion of the total of the constituent unit (1) and the constituent unit (2) in all constituent units of the copolymer is 80 mol % or more. 
     
     
         7 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein a molar ratio of the constituent unit (1) and the constituent unit (2) in the copolymer, constituent unit (1)/constituent unit (2), is 1 or more and 10 or less. 
     
     
         8 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein a pH of the mixture of the copolymer is adjusted with a hydroxide of an alkali metal or an alkaline-earth metal. 
     
     
         9 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein the copolymer has a weight average molecular weight of 20,000 or more and 70,000 or less. 
     
     
         10 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein q in the formula (2) is 1. 
     
     
         11 : The method for producing a powder dispersant composition for hydraulic compositions according to  claim 2 , wherein a powder dispersant composition for hydraulic compositions having a median diameter (D50) of 1 μm or more and 90 μm or less and a proportion of particles with a particle size of 1 μm or more and 250 μm or less of 90 mass % or more and 100 mass % or less is produced. 
     
     
         12 : A powder dispersant composition for hydraulic compositions produced by the method according to  claim 2 , wherein the powder dispersant composition for hydraulic compositions has a median diameter (D50) of 1 μm or more and 90 μm or less and a proportion of particles with a particle size of 1 μm or more and 250 μm or less of 90 mass % or more and 100 mass % or less. 
     
     
         13 : A powdered hydraulic composition formulated with a hydraulic powder and the powder dispersant composition for hydraulic compositions according to  claim 12 .